Updated
An uptick in the number of emaciated sea turtles washing up along the northern New South Wales coastline has conservationists worried.
Key points:
- Conservationists report higher numbers of "emaciated" sea turtles along northern NSW beaches
- Ecologist says sea turtles are moving further south as water and sand temperatures rise, presenting conservation challenges
- It is estimated that only one out of every 1,000 turtle hatchlings survive to reach maturity
Australian Seabird Rescue, which operates a rehab clinic for turtles in Ballina, has no answers for why they are finding more of the marine reptiles on the state's beaches.
"There's not a lot of data for New South Wales on sea turtles," general manager Olly Pitt said.
"There's quite a large number this year of emaciated sea turtles.
"What's causing that? I don't know, but it would be good to get some answers soon."
But, as water temperatures in the Coral Sea spike, causing widespread bleaching along the Great Barrier Reef, the number of sea turtles nesting south of the border is likely to rise.
Whistler and Jay Jay draw a big crowd
This week, about 200 people gathered at Kingscliff beach to watch the release of two green sea turtles, Whistler and Jay Jay.
Ms Pitt said Whistler washed up at Kingscliff last November "completely emaciated, covered in barnacles".
"He wasn't eating when he first came in but since then, since November, has made a full recovery," she said.
Ms Pitt said Jay Jay was found further north, at Fingal, with a wound under his back flipper that "looked like a massive hook had gone in".
"This past summer, we've probably seen about five [turtles] in Kingscliff to Fingal alone," she said."We also have another 18 turtles in care at the moment, so it's been a really busy summer."
Ms Pitt said while she has felt encouraged by the public's strong interest, she was concerned about the relatively high numbers of animals coming into their care.
"I do see a lot of healthy turtles out in the bay in Byron, however what's washing up on our beaches isn't the same case," she said.
Turtles moving south as waters warm
Professor of Ecology at the University of New South Wales Tracey Rogers said sea turtles are "turning up in greater numbers" south of the border, particularly between Tweed Heads and Coffs Harbour, due to higher water temperatures."Typically, they would nest in Queensland in beaches like Mon Repos near Bundaberg," she said.
"This year, we even had a Green turtle nest on Manly beach here in Sydney, which is a long way from Queensland."
"For a turtle to nest off Sydney, I've never heard of it before."Dr Rogers said warmer-than-average temperatures mean the "prime areas for the turtles to nest are shifting south".
"The temperature of the sand dictates the sex that [hatchlings] will be," she said.
"At these very southern colonies, where it's cooler, more of them are going to be male, so these New South Wales hatchling colonies are going to become important.
"So, the turtles are moving down with this warmer water but also away from that very hot sand up north."
In 2018, the Queensland Government trialled the use of sprinklers at Mon Repos Beach near Bundaberg, to decrease sand temperatures after the rate of eggs hatching halved.
Movement south presents conservation challenges
Dr Rogers said with a higher density of development along the NSW coastline, nesting turtles faced significant threats."[Hatchlings] use the light of the moon as an orientation to get to the water," she said.
"If they've got a row of houses behind them with lights, then they get disorientated and go the wrong way."With other threats including marine debris, predators including feral species, and coastal erosion, Dr Rogers said it was increasingly important for turtle nests to be conserved and left undisturbed where possible.
Meanwhile, Australian Seabird Rescue has partnered with the NSW Government to develop the TurtleWatch program, which encourages the public to report nest locations and help conservation efforts.
Ms Pitt said releasing rescued turtles back into the wild was a valuable way of improving public awareness and education.
"It's so special, you see all the kids' faces here today before school and they'll go to school and talk about this with all their friends and that'll really make a difference for sea turtles in the future," she said.
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